But, for all that, the text leaves unanswered at least as many questions as it resolves. In reality -- and as the coming weeks, months, and years will demonstrate -- major issues have yet to be settled. It is closer to the truth to say the real debate about the Iran nuclear accord is just beginning.

The framework places significant limits on Iran's nuclear program, including the number and type of centrifuges, the sort of reactors and the amount and quality of enriched uranium that the country may possess. Standards are set for the inspections needed to provide confidence that Iran is fulfilling its obligations. And provision is made for easing economic sanctions once Iran has verifiably met its commitments.

The bottom line is that the agreement will provide an estimated one-year warning from the moment that Iran might decide to build one or more nuclear weapons to the point at which it could achieve that goal. This assessment assumes that the monitoring called for in the accord will detect any Iranian non-compliance early enough to enable a coordinated international response, particularly the reintroduction of sanctions, before Iran could acquire nuclear weapons.

There are no less than five reasons not to assume the deal will enter into force or have the desired impact.

2. A second concern stems from the specific issues that remain to be resolved.

The most difficult might be the timing of when various economic sanctions are to be removed -- the issue of greatest concern to Iran. But these same sanctions are also the source of the greatest leverage over Iranian behavior, which means that many in the U.S. and Europe will want them to remain in place until Iran has fully met its critical obligations.

3. A third source of doubt is whether the various parties will approve any long-term pact.

The uncertainties are greater in the U.S.. President Barack Obama must contend with a far more complex political environment, beginning with the U.S. Congress. There is widespread and understandable concern about leaving Iran with any nuclear capabilities, about the adequacy of provisions for monitoring and inspection, and about what will happen in 10 or 15 or 25 years when various limits on Iran expire. Persuading Congress to approve the final pact and/or lift sanctions is anything but assured.

4. This question of gaining political approval is closely tied to a fourth area of concern: how any final agreement is implemented.

Iran is a would-be imperial power that seeks regional primacy. Even a nuclear agreement that is signed and implemented will not affect this reality and might even make it worse, as Iran could well emerge with its reputation enhanced and a long-term option to build nuclear weapons intact.